Sandy Cobblestone — Java Edition 26.2 — v4.2

NORMAL SANDSTONE — one grouped recipe-book entry
- 4 Sand = 1 Sandstone
  Recipe ID: sandy_cobblestone:sandstone_from_sand
  Unlock: obtain Sand.
- 1 Sand + 1 Cobblestone = 1 Sandstone
  Recipe ID: sandy_cobblestone:sandstone
  Unlock: have Sand and Cobblestone in the inventory at the same time.

RED SANDSTONE — one grouped recipe-book entry
- 4 Red Sand = 1 Red Sandstone
  Recipe ID: sandy_cobblestone:red_sandstone_from_red_sand
  Unlock: obtain Red Sand.
- 1 Red Sand + 1 Cobblestone = 1 Red Sandstone
  Recipe ID: sandy_cobblestone:red_sandstone
  Unlock: have Red Sand and Cobblestone in the inventory at the same time.

V4.2 CHANGES
- Removes all one-time migration logic from V4.
- Makes no attempt to repair recipe-book state from V3.
- Assumes the player has not previously loaded V3.
- Recipes are unlocked only by their normal ingredient-based advancements.

GROUPING AND VANILLA COMPATIBILITY
- The vanilla recipe JSON files minecraft:sandstone and minecraft:red_sandstone are not
  replaced. They remain loaded and manually craftable.
- Custom copies of the four-sand recipes are used for the recipe book because a recipe's
  group is stored in its own recipe JSON and the vanilla sandstone recipes have no group.
- The vanilla recipe-unlock advancements are replaced so the grouped custom copies are
  shown instead of duplicate ungrouped vanilla buttons.
- Once the cobblestone variant is unlocked, the single recipe-book button cycles between
  the four-sand and sand-plus-cobblestone inputs.

INSTALLATION
1. Remove older versions of this pack from the world's datapacks folder.
2. Put this ZIP directly in <world>/datapacks/.
3. Run /reload or reopen the world.

TESTING
For a clean unlock test, use a player with no Sand, Red Sand, or Cobblestone. The
four-sand entry appears after obtaining the matching sand. Its cobblestone variant is
added to the same grouped entry only after the matching sand and Cobblestone are held
at the same time.
